Metallocene catalyst supported by hybrid supporting means, process for producing same, polymerization process for producing an ethylene homopolymer or copolymer with broad or bimodal molar mass distribution, use of the supported metallocene catalyst and ethylene polymer with broad or bimodal molar mass distribution

ABSTRACT

The present invention describes a metallocene catalyst based on a transition metal of group 4 or 5 of the periodic table; supported on a hybrid catalytic support with aliphatic organic groups and a process for supporting metallocene on the hybrid catalytic support. The supported metallocene catalyst provides an ethylene polymer with broad or bimodal molecular weight distribution in the presence of only one metallocene complex on the support.

BACKGROUND OF THE INVENTION

The present invention relates to a metallocene catalyst based on atransition metal from group 4 or 5 of the periodic table which issupported by hybrid catalyst supporting means with aliphatic organicgroups.

One also describes the process for supporting metallocene on said hybridcatalytic supporting means with aliphatic organic groups.

The main advantage of the supported metallocene catalyst of the presentinvention is that an ethylene polymer with broad or bimodal molar massdistribution is produced by using only one type of metallocene complexon the supporting means. As a result, the resin produced can beprocessed in an improved manner, and one obtains a potential reductionof processing costs.

There are many researches involving the development of metallocenecatalysts. These catalysts, due to the fact that they have a singleactive center, enable the production of polyolefins with properties thatare differentiated in terms of molecular mass, molar mass distribution,stereoregularity and incorporation and co-monomer distribution.

Particularly, polymers that have a narrow distribution of molar massexhibit better physical properties, such as resistance to impact and to“environmental stress cracking”, as well as film transparency. However,these polymers exhibit processing difficulty due to their restriction inthe distribution of molar mass.

In general, a broad distribution of molar mass provides greater fluidityof the polymer in the molten state, facilitating the processing thereof.

Thus, a few strategies for broadening the distribution of molar mass ofpolyolefins produced by using metallocene catalysts have been developedin the prior art. Among them we can cite: (i) blends of polymersproduced by two different catalysts such as described in U.S. Pat. No.6,649,698 and U.S. Pat. No. 6,787,608; (ii) use of multi-reactortechnology as described in WO07336A1; U.S. Pat. No. 6,566,450; U.S. Pat.No. 7,488,790, and WO/2005/005493; (iii) combination of two metallocenesthat are not supported on the polymerization of olefins, as mentioned inUS. Pat. No. 0,234,547A1 and US2011257348A1; and (iv) polymerization ofolefins by using a catalyst prepared by immobilizing two differentmetallocenes or one metallocene and one non-metallocene in the samesupport, as for instance in U.S. Pat. No. 719,302B2; U.S. Pat. No.7,312,283B2; U.S. Pat. No. 6,943,134B2; U.S. Pat. No. 0,183,631A1; U.S.Pat. No. 5,525,678A; U.S. Pat. No. 7,199,072B2; U.S. Pat. No. 199,072b2;U.S. Pat. No. 6,686,306B2, and U.S. Pat. No. 6,001,766A.

The use of catalytic systems for polymerizing olefins comprisingsupported metallocene catalysts comprising inorganic supports isextensively described in the literature (Hlatky, Chem. Rev. 100 (2000)1347-1376; Severn et alli, Chem Rev. 105 (2005) 4073-4147).

As can be seen from the prior art, silica has been the inorganic supportat that is most widely employed in the development of supportedmetallocene catalysts. The surface and reactivity of the functionalsilica groups (isolated silanols, vicinal and geminal silanols, andsiloxane) are well known. Obtaining them involves well-known pathways,among which is precipitation (precipitated silicas), and resulting fromhydrolysis and reactions and condensation (xerogel silicas, aerogels,hydrogels). See, example, US 1970/3505785; US1971/3855172;DE1972/2224061; US1974/3668088; DE1975/2505191; US1975/3922393;DE1977/2719244; DE1976/2628975; US1979/4179431; EP1980/0018866;DE1986/3518738; DE1989/0341383; EP1989/0335195A2; US 1992/5118727 and US1998/5723181.

Various pathways for preparing supported metallocene catalysts have beendescribed in the literature and may be classified into:

(i) direct immobilization on silica as described in Santos et alli,Macromol. Chem. Phys. 198 (1997) 3529; Dos Santos et alli, J. Mol. CatalA; 139 (1999) 199; Dos Santos et alli, Macromol. Chem. Phys. 200 (1999)751);

(ii) immobilization on silica functionalized with methylaluminoxane(herein referred to as MAO), or with other types of catalysts, asdescribed in US1989/4808561; US1989/4871705; US1990/4912075;US1990/4914253; US1990/4925821; US1990/4935397; US1990/4925217;US1990/4921825; US1991/5026797; US1991/5006500; US1992/5086025;US1993/5328892; WO1994/26793; US1995/5462999; WO1996/04318; US1995/5468702; EU1997/849286; WO1997/42228; US1997/5629253;US1997/5661098; EU1998/922717; EU1998/856525; US1998/5712353;US1998/5739368; US1998/5763543; US1998/5719241; EU1999/989139;US1999/5968864; EU2000/1038855; US2000/6034024; WO2001/12684;WO2001/40323; US2001/6214953; EU2001/1167393; US2001/0051587;US2001/0053833; EU2002/1231225; US2002/40549; US2002/0107137;US2003/236365 and WO2004/055070;

(iii) synthesis of metallocene situ on the support, as described inJP1990/0485306; US1996/5504408; US998/5739226; US2002/6399531; andUS2002/326005;

(iv) Immobilization on hybrid silica, as described in: Dos Santos etalli, Appl. Catal. A: Chemical 220 (2001) 287-392; Dos Santos et alli,Polymer 42 (2001) 4517-4525; Dos Santos et alli, J. Mol. Catal. A:Chemical 158 (2002) 541-557; and

(v) Immobilization on silicas modified with spacers, as describes, forexample, in US1995/5397757; US1995/257788 and US1997/5639835.

The pathway (i) consists of the reaction between the silica silanolgroups and the group that gives off the metallocene (chloride orhydride) in the presence of an organic solvent. The pathway (ii)essentially comprises pre-contact of the support with MAO or otheralkylaluminums, followed by immobilization of the metallocene. In thepathway (iii), the silanol groups of the silica surface are reacted withcompounds of the type MCl4 (M=Ti, Zr) and then with indenyl orcyclopentadienyl ions, or the silanol groups of the silica surface arereacted organosilanes provided with ligands of the cyclopentadiene orindene type, which by deprotonation generate aromatic ions that may bemetallized with reactants of the type MCl4 (M=Ti, Zr). Hybrid-silicaimmobilizing pathways (pathway iv) consist in obtaining a silicacontaining organic groups on the surface, obtained by the sol-gelmethod, followed by metallization. This pathway differs from thepreceding one in that in pathway (iii) the silica employed iscommercial, previously synthesized, whereas in the latter pathway thesilica is synthesized already with the organic ligands (hybrid silicas).The pathway (iv) differs from the present invention in that the hybridsilica does not contain aliphatic organic groups and, therefore, doesnot generate a catalyst capable of producing polyethylenes that arebimodal or have broad distribution of molar mass. Finally, in the lastpathway, the catalytic sites are generated or pushed off the surface(vertical spacers) or from each other (horizontal spacers). In bothcases, the objective is to increase the catalytic activity of thesesupported metallocene catalysts.

In the open literature, examples of these five pathways are commented inthe bibliographic revisions of Hlatky (Chem. Rev. 100 (2000) 1347-1376)and of Severn et al (Chem Rev. 105 (2005) 4073-4147). Examples of thesemethodologies can also be found in documents WO 2006/131704; WO2006/131703; JP 2006/233208; US 2006/135351; US 2006/089470; JP2006/233208; US 2001/6239060 and EP 2000/1038885.

Most patent documents that use chemically modified silica employs sometype of commercial silica and modify it by grafting reactions orimpregnation.

WO 2006/131704 describes the preparation of a supported catalyst, onwhich, after pre-contacting the co-catalyst with the catalyst(transition metal compounds, particularly metallocenes), in mole rationlower than 10:1, the mixture is contacted with a porous support,followed by removal of the solvent (impregnation method). Thepreparation method is simple, without implying loss of activity. Thesame thing happens in US 2006/089470, in which a homogeneous metallocenecatalyst and a combination of alkylaluminoxane and alkylaluminum aresupported on silica, with average size of 540 μm. Metallocene catalystand co-catalyst (aluminoxane or alkylaluminum) are also pre-contactedbefore being immobilized on spheroidal silica (5-40 μm) according topatent EP 200/1038885. In this case, 50% of the catalytic component isimmobilized inside the support pores, which guarantees the production ofa product having few gel imperfections.

In WO 2006/131703, the porous support is pre-treated with a dehydratingagent and with a hydroxylated compound. The resulting support is thenreacted with the catalyst (transition metal compound, such asmetallocene, for example) and co-catalyst. The resulting supportedcatalyst is provided with enhanced catalytic activity. In document JP2006/233208, the support is also pre-treated, but in this case withaluminoxane compounds, such as MAO, followed by reaction withmetallocene. In this case, a part of the support is reacted with anansa-metallocene and a part with an ansa-fluorenylmetallocen. In bothcases, the metallocenes are individually treated withtri-isobutylaluminum (herein referred to as TIBA) and with 1-hexane. Thefinal catalytic system is constituted by the combination of the twosupported metallocenes and is active for co-polymerization of ethyleneand 1-hexene. In US 2001/6239060, silica, after acidic treatment (HCl)and thermal treatment (110 and 800° C.), is functionalized previouslywith alkylaluminum and then contacted with metallocene-aluminoxanemixture. In WO 2002/038637, the process of preparing the supportedmetallocene catalyst is carried out by successive reaction of silicawith ordinary alkylaluminum, and with borate derivatives, followed byaddition of an ansa-metallocene. The final catalyst, active in theco-polymerization of ethylene and/or propylene with alpha-olefins,guarantees high contents of incorporated co-monomer.

Organoaluminums of the type Et₂AlH and Et₂Al(OEt) were proposed assilica modifying agents in document WO 2003/053578. The resulting silicaserved as a support for immobilizing metallocene. The resulting systemexhibited an increase in catalytic activity, attributed to theadditional presence of co-catalysts on the silica surface.

JP 2003/170058 describes the preparation of a support in whichcommercial silica pre-modified with ordinary alkylaluminum and withcompounds having electroactive groups, such as 3,4,5-trifluorofenol. Themodified silica is employed in the co-polymerization of olefins as acomponent of the catalytic system constituted by a metallocene andcommon alkylaluminum. This is no preparation of the final supportedcatalyst, but rather in situ immobilization, in which the ultimateheterogenization process takes place in situ, inside the polymerizationreactor.

JP 2006/274161 teaches the preparation of active supported catalysts forco-polymerization of olefins, capable of polymerizing ethylene and1-butene in the presence of common alkylaluminums and producingco-polymers with short branching and molar mass distribution (hereinreferred to as DPM) of 6.8. Such catalysts use silica functionalizedwith organometallic compounds with metal of the groups 1 and 2, as forexample Et2Zn, which is then treated in a number of steps withelectron-donating organic solvents, water, before the immobilization ofan ansa-metallocene.

US 2006/135351 describes the preparation of the supported catalyst,wherein the metallocene has a functional group that facilitates andleads to a strong bond with the silica surface, used as support,minimizing bleaching processes. According to the technical descriptionof this document, the polymerization takes place without “fouling” inthe reactor, in both slurry process and in gaseous phase, and themorphology and density of the polymer produced are much better defined.

Lewis bases such as pentafluorofenol were also used in the modificationof silica. The immobilization of metallocenes and organometalliccompounds such as chromocene, on the same support (silica) modified withLewis bases and alkylaluminum generate active catalysts in theco-polymerization of ethylene and 1-hexene, with DPM of 10.9.

WO 2004/018523 describes a process of preparing supported metallocenecatalyst, in which the support (silica) is synthesized by anon-hydrolytic sol-gel process by condensing a silane containing anionicligands, of a halogenated silane (r siloxane) and an alkoxysilane. Thehybrid silica generated is then subjected to a metallization reaction,and the resulting catalyst is active, in the presence of a co-catalyst,in processes of polymerization olefins, in gaseous phase.

As can be seen from the prior art, it is not described or expected thatthe immobilization of a single metallocene complex on a silica-basesupport results in a polyethylene with broad or bimodal massdistribution. Moreover, the use of hybrid silica provided with aliphaticorganic groups, prepared by the sol-gel process, as a support formetallocene was not reported in the literature.

Thus, the present invention relates to metallocene catalysts based ontransition metal of the groups 4 and 5 of the periodic table, supportedon a hybrid support for the production of homopolymers or copolymers ofethylene with alpha-olefins with broad or bipolar molar massdistribution.

One also describes a process of preparing metallocene catalystssupported on a hybrid catalytic support and a process for the productionof homopolymers or copolymers of ethylene with alpha-olefins with broador bimodal molar mass distribution.

The supported metallocene catalyst of the present invention exhibits, asits main advantage, the fact that it produces an ethylene polymer withbroad or bimodal molar mass distribution using only one type ofmetallocene complex on the support. As a result, one obtains betterprocessability of the resin obtained and, therefore, a potentialreduction of the processing cost.

OBJECTIVES OF THE INVENTION

The present invention provides a metallocene catalyst based ontransition metal of the groups 4 and 5 of the periodic table, supportedon a hybrid catalytic support having aliphatic organic groups.

One also describes a process for supporting metallocene on said hybridsupport having aliphatic organic groups.

The present invention also relates to a hybrid catalytic supportcontaining aliphatic organic groups and to the process of preparing it,by means of a hydrolytic sol-gel pathway.

Finally, the present invention relates to a process of producinghomopolymers of ethylene and copolymers of ethylene with alpha-olefinswith broad or bimodal molar mass distribution.

The supported metallocene catalyst of the present invention exhibits, asits main advantage, the fact that one produces a polymer of ethylenewith broad or bimodal molar mass distribution by using only one type ofmetallocene complex on the support. As a result, one obtains betterprocessability of the resin obtained and, therefore, a potentialreduction of processing cost.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a metallocene catalyst based ontransition metal of the group 4 or 5 of the periodic table, supported onthe hybrid catalytic support having aliphatic organic groups.

A process of supporting metallocene on the hybrid catalytic support anda process of homopolymerizing ethylene or copolymerizing ethylene withalpha-olefins with broad or bimodal molar mass distribution are alsodescribed.

The metallocene catalyst supported on a hybrid catalytic support of theinvention comprises:

(I) at least one metallocene derived from a compound of formula 1:[L]₂-MQ₂ Formula (1),

wherein:

M is a transition metal of the group 4 or 5 of the periodic table;

Q, which may be equal or different, comprise: halogen radical, arylradical, alkyl radical containing 1 to 5 carbon atoms or alkoxy radicalcontaining to 5 carbon atoms; and

L is a ligand selected from: cyclopentadienyl, indenyl or fluorenyl,either substituted with hydrogen or not, alkyl, cycloalkyl, aryl,alkenyl, alkylaryl, arylalkyl or arylalkenyl, attached to the transitionmetal by bonding;

(II) a hybrid catalytic support having at least one inorganic componentand aliphatic organic groups.

Preferably, the supported metallocene catalyst comprises at least oneorganometallic reactant containing a metal selected from the groups 2 or13 of the periodic table.

The process of obtaining supported metallocene catalysts based ontransition metal of groups 4 or 5 of the periodic table of the presentinvention comprises:

a) preparing the hybrid support having aliphatic organic groups;

b) reacting the hybrid support obtained in step (a) with anorganometallic reactant;

c) reacting the product obtained in step (b) with the metallocene.

In a preferred embodiment, the hybrid catalytic support is preparedaccording to the following steps:

-   i) preparing an aqueous solution of a base diluted in alcohol;-   ii) adding a tetraalkylorthosilicate solution to the solution    obtained in (i);-   iii) reacting a trialkoxydoorganosilicate solution with the solution    obtained in (ii);-   iv) removing the solvent from the product of the reaction obtained    in (iii).

Preferably, the hybrid catalytic support is impregnated with a solutionof organometallic compound from the groups 2 or 13 of the periodictable, in an inert organic solvent.

In a preferred embodiment, the hybrid support obtained afterimpregnation reacts with a metallocene solution based on transitionmetal of the groups 4 or 5 of the periodic table in an inert organicsolvent. After said reaction, the supported catalyst is washed and thesolvent is removed.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1—image of scanning electron microscopy of the hybrid supportobtained in Example 1;

FIG. 2—image of scanning electron microscopy of the hybrid supportobtained in Example 3;

FIG. 3—image of scanning electron microscopy of the hybrid supportobtained in Example 4;

FIG. 4—image of scanning electron microscopy of the hybrid supportobtained in Example 5;

FIG. 5—image of scanning electron microscopy of the hybrid supportobtained in Example 6;

FIG. 6—GPC curve for the polyethylene prepared with the catalystobtained in Example 8;

FIG. 7—GPC curve for the polyethylene prepared with the catalystobtained in Example 9;

FIG. 8—GPC curve for the polyethylene prepared with the catalystobtained in Example 7 (comparative).

DETAILED DESCRIPTION OF THE INVENTION

For a better understanding of the terms to be mentioned in the presentspecification, one should consider the following abbreviations andclarifications:

-   hybrid support: a material constituted by an inorganic component and    by at least one organic component;-   TEOS: tetraethoxylane;-   C contents: total percentage by mass of carbon in the hybrid    catalytic support, determined by CHN on a CHN catalyst model 2400,    manufactured by Perkin Elmer;-   Zr contents: total percentage by mass of zirconium in the supported    metallocene catalyst, determined by Rutherford backscattering    spectrometry on a 500 kV HVEE ion implanter;-   Al contents: total percentage by mass of aluminum in the supported    metallocene catalyst, determined by SEM-EDX under a scanning    electron microscope with energy-dispersive X-ray spectroscopy y    spectrometer model JSM, manufactured by JEOL;-   TEAL: triethylaluminum;-   L₂MX₂: metallocene complex;-   Al/SiO2: ratio in weight percentage of transition metal belonging to    the group 4 or 5 of the periodic table on silica, determined by    Rutherford backscattering spectrometry on a 500 kV HVEE ion    implanter. Al/M: mole ratio between aluminum of the co-catalyst and    transition metal of the supported complex belonging to the group 4    or 5 of the periodic table;-   Catalytic activity: it represents the yield in kilograms (kg) of    polymer produced per mole of transition metal belonging to the group    4 or 5 of the periodic table, present in the catalyst, and per hour    of reaction;-   T_(m): it represents the measurement of the melting temperature in    ° C. of the polymer, determined by Differential Scanning Calorimetry    effected on a DSC 2920 analyzer manufactured by TA instruments;-   GPC: gel-permeation chromatography;-   M_(w): it represents average weight molecular mass of the polymers,    determined by GPC effected on a GPCV 2000 equipment manufactured by    Waters;-   M_(w)/M_(n): it represents the molar mass distribution determined    from the GPC curve effected on a GPCV 2000 Waters equipment.

The hybrid catalytic support of the present invention is constituted byan inorganic component, preferably silica, and an organic component.Said organic component is constituted by aliphatic hydrocarbons (oraliphatic organic groups) with chain containing 1 to 40 carbon atomsbonded covalently to the inorganic component. Preferably, the aliphatichydrocarbons used in the present invention contain from 8 to 22 carbonatoms.

The hybrid catalytic support of the present invention exhibits aliphaticorganic groups dispersed homogeneously at molecular level, both on thesurface of the organic component and inside it.

The hybrid catalytic support of the present invention is preferablyobtained by means of a sol-gel pathway. The sol-gel pathway described inthe present invention refers to a hydrolytic pathway in a base medium,wherein the base acts as a catalyst of the sol-gel reaction. This baseaccelerates the hydrolysis reaction and condensation reaction of thereactants present in said reaction.

The hybrid catalytic support of the present invention preferably hasspherical and lamellar morphology and is provided with aliphatic organicgroups.

In a preferred embodiment, the process of preparing the hybrid catalyticsupport comprises the following steps:

-   i) diluting an aqueous solution of a base in an alcohol;-   ii) adding an alcoholic solution of tetraalkylorthosilicate onto the    solution obtained in steps (i);-   iii) reacting a solution of trialkoxydoorganosilane with the    solution obtained in step (ii); and-   iv) removing the solvent that is present in the reaction product    obtained in step (iii).

According to step (i) of the process of preparing the catalytic supportof the present invention, the aqueous solution of a base withconcentrations ranging from 0.1 to 5 mole/L is diluted in an alcohol.

The dilution factor (aqueous solution of a base/alcohol) ranges from 10to 300. Preferably, one uses the dilution factor of 100.

The bases that may be used in step (i) of preparing the hybrid catalyticsupport are selected from hydroxides of the group I and II, aliphaticand aromatic amines, ammonium hydroxide and/or mixture thereof.Preferably, ammonium hydroxide is used. The pH of the base solutionranges from 8 to 14.

The alcohols that may be used in step (i) of preparing the hybridcatalytic support are selected from: methanol, ethanol, 1-propanol,2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 1-hexanol,2-hexanol and/or mixtures thereof. Preferably, ethanol is used.

The aqueous base solution and the alcohol are subjected to stirring, thestirring velocity ranging from 50 rpm to 40,000 rpm.

In step (ii) of the process of preparing the hybrid catalytic support,an alcoholic solution of tetraalkylorthosilicate is added on thesolution obtained in (i).

The alcohols used in step (ii) comprise: methanol, ethanol, 1-propanol,2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 1-hexanol,2-hexanol and/or mixtures thereof.

Non limiting examples of the tetraalkylorthosilicates that are used inthe present invention include: tetramethylorthosilicate (TMOS),tetraethylorthosilicate (TEOS), tetrapropylorthosilicate (TPOS),tetrabutylorthosilicate (TBOS) and/or mixtures thereof. Preferably, TEOSis used.

The stirring velocity of the mixture obtained in step (ii) is keptbetween 50 and 40,000 rpm.

The reaction time of this mixture ranges from 0.1 to 24 hours.Preferably, 2 hours are used. This mixing and stirring step may also becarried out simultaneously in step (iii).

Step (iii) of the process of preparing the hybrid catalytic supportcomprises reacting a trialkoxyorganosiliane with the solution obtainedin step (ii).

The trialkoxyorganosilane has carbon chain ranging from 1 to 40 carbonatoms. Preferably, a trialkoxyorganosilane with 8 to 22 carbon atoms isused.

The alkoxide grouping of said reactant should have from 1 to 4 carbonatoms. Preferably, the alkoxide grouping with 1 carbon atom is used.

Non-limiting examples of trialkoxyorganosilanes that are used in thepresent invention include: hexadecyltrimethoxysiliane (HDS),heptadecyltrimethoxysiliane (HPDS), octadecyltrimethoxysiliane (ODS),hexadecyltriethoxysiliane (HDES), heptadecyltriethoxysilane (HPDES),octadecyltriethoxysilane (ODES) and/or mixture thereof. Preferably, ODSis used.

The mole ratio of trialkoxyorganosilane:tetraalkylorthosilicate rangesfrom 1:0 to 1:100, preferably from 1:1 to 1:60.

The addition of trialkoxyorganosilane to the solution obtained in (ii)may be made concomitantly or until 24 hours after addition oftetraalkylorthosilicate. Preferably, the addition oftrialkoxyorganosilane is carried out 2 hours after addition oftetraalkylorthosilicate. The reaction is kept for an additional timeranging from 0.1 to 48 h, preferably 2 hours.

The stirring velocity during the reaction should be kept between 50 and40,000 rpm. Preferably, one uses a stirring velocity of 150 rpm. Thisstep may be carried out simultaneously with step (ii).

In step (iv) of the process of preparing the hybrid catalytic support,one carries out the removal of the solvent that is present in thereaction product obtained in (iii).

The removal of the solvent may be carried out by evaporation at roomtemperature, filtration, centrifugation, or under reduced pressure.Preferably, one uses reduced pressure in a time ranging from 1 to 24hours.

The contents of aliphatic organic groups, measured through the Ccontent, of the hybrid catalytic support, obtained in theabove-described process, range from 0.5 to 80%. The number of aliphaticorganic groups in the catalytic hybrid supports influences the Mw/Mn ofthe ethylene polymers.

The metallocene catalyst supported in a hybrid catalytic support havingaliphatic organic groups of the invention comprises:

at least one metallocene derived from a compound of formula 1: [L₂-MQ₂formula (1),

wherein:

M is a transition metal of the group 4 or 5 of the periodic table;

Q, which may be equal or different, comprise: halogen radical, arylradical, alkyl radical containing 1 to 5 carbon atoms or alkoxy radicalcontaining to 5 carbon atoms; and

L is a ligand selected from: cyclopentadienyl, indenyl or fluorenyl,either substituted with hydrogen or not, alkyl, cycloalkyl, aryl,alkenyl, alkylaryl, arylalkyl or arylalkenyl, attached to the transitionmetal by bonding;

a hybrid catalytic support having at least one inorganic component andaliphatic organic groups.

Preferably, the supported metallocene catalyst comprises at least oneorganometallic reactant containing a metal selected from the groups 2 or13 of the periodic table. More preferably, in the process of preparingthe metallocene catalysts, one carries out impregnation of the hybridsupport obtained in the preceding step (iv), with a solution oforganometallic compound of group 2 or 13 of the periodic table, in aninert organic solvent.

The organometallic compounds that may be used in the step ofimpregnating the hybrid support are selected from: trimethylaluminum(TMAL)\, triethylaluminum (TEAL), tri-isobutylaluminum (TIBAL),tri-n-hexylaluminum (TNHAL), tri-n-octylaluminum (TNOAL),dimethylaluminum chloride (DMAC), methylaluminum dichloride (MADC),dimethylaluminum dichloride, ethylaluminum dichloride (EADC),di-isobutylaluminum chloride (DIBAC), isobutylaluminum dichloride(MONIBAC), butyl ethylmagnesium (BEM), butyl octylmagnesium (BOMAG),methyl magnesium chloride, ethylmagnesium chloride and/or mixturesthereof. These compounds may be used in the concentrated or dissolvedform. In a preferred embodiment, one uses dissolved compounds in anorganic solvent of the aliphatic hydrocarbon type.

When using more than one organometallic compound of the group 2 or 13 ofthe periodic table in the step of impregnating the hybrid support, thedifferent compounds may be fed to the same solution or to individualsolutions, either at the same time or in subsequent additions.

Non-limiting examples of inert organic solvents that may be used forsolubilizing the organometallic compound of the group 2 or 13 of theperiodic table are selected from: toluene, cyclohexane, n-hexane,n-heptane and n-octane and/or mixtures thereof.

In the step of impregnating the hybrid catalytic support one employs anamount of solvent sufficient to suspend the material.

The amount of organometallic compound of the group 2 or 13 of theperiodic table that may be used ranges from 1 to 60% by mass of metalwith respect to the mass of hybrid catalytic support. Preferably, oneshould use an amount ranging from 5 and 30% of metal.

The reaction time of the step of impregnating the hybrid support shouldrange from 0.1 h to 24 h, preferably from 0.5 h to 3 h, and the reactiontemperature ranges from −10 C to 80° C., preferably from 0 to 30° C.

After impregnation, the hybrid catalytic support obtained reacts with ametallocene solution based on transition metal of groups 4 or 5 of theperiodic table in an inert organic solvent.

The metallocene is derived from a compound of formula 1:formula (1),[L₂-MQ₂  (I)wherein:

M is a transition metal of the group 4 or 5 of the periodic table;

Q, which may be equal or different, comprise: halogen radical, arylradical, alkyl radical containing 1 to 5 carbon atoms or alkoxy radicalcontaining to 5 carbon atoms; and

L is a ligand selected from: cyclopentadienyl, indenyl or fluorenyl,either substituted with hydrogen or not, alkyl, cycloalkyl, aryl,alkenyl, alkylaryl, arylalkyl or arylalkenyl, attached to the transitionmetal by bonding.

Representative but non-limiting examples of compounds having the formula1 include: Cp₂TiCl₂, Cp₂ZrCl₂, Cp₂HfCl₂, Cp₂VCl₂, Cp₂Ti(Me)₂,Cp₂Zr(Me)₂, Cp₂Hf(Me)₂, Cp₂Ti(OMe)₂, Cp₂Zr(OMe)₂, Cp₂Hf (OMe)₂,Cp₂Ti(OEt)₂, Cp₂Zr(OEt)₂, Cp₂Hf(OEt)₂, Ind₂TiCl₂, Ind₂ZrCl₂, Ind₂HfCl₂,Ind₂VCl₂, Ind₂Ti(Me)₂, Ind₂Zr(Me)₂, Ind₂Hf(Me)₂, Ind₂Ti(Me)₂,Ind₂Zr(OMe)₂, Ind₂Hf(OMe)₂, Ind₂Ti(OEt)₂, Ind₂Zr(OEt)₂, Ind₂Hf(OEt)₂,Flu₂TiCl₂, Flu₂ZrCl₂, Flu₂HfCl₂, Flu₂VCl₂, Flu₂Ti(Me)₂, Flu₂Zr(Me)₂,Flu₂Hf(Me)₂, Flu₂Ti(OMe)₂, Flu₂Zr(OMe)₂, Flu₂Hf(OMe)₂, Flu₂Ti(OEt)₂,Flu₂Zr(OEt)₂, Flu₂Hf(OEt)₂, (MeCp)₂TiCl₂, (MeCp)₂ZrCl₂, (MeCp)₂HfCl₂,(MeCp)₂VCl₂, (MeCp)₂Ti(Me)₂, (MeCp)₂Zr(Me)₂, (MeCp)₂Hf(Me)₂,(MeCp)₂Ti(OMe)₂, (MeCp)₂Zr(OMe)₂, (MeCp)₂Hf (OMe)₂, (MeCp)₂Ti(OEt)₂,(MeCp)₂Zr(OEt)₂, (MeCp)₂Hf(OEt)₂, (nBuCp)₂TiCl₂, (nBuCp)₂ZrCl₂,(nBuCp)₂HfCl₂, (nBuCp)₂VCl₂, (nBuCp)₂Ti (Me)₂, (nBuCp)₂Zr(Me)₂,(nBuCp)₂Hf(Me)₂, (nBuCp)₂Ti(OCH₃)₂, (nBuCp)₂Zr (OCH₃)₂,(nBuCp)₂Hf(OCH₃)₂, (nBuCp)₂Ti(OEt)₂, (nBuCp)₂Zr (OEt)₂,(nBuCp)₂Hf(OEt)₂, (Me₅Cp)₂TiCl₂, (Me₅Cp)₂ZrCl₂, (Me₅Cp)₂HfCl₂,(Me₅Cp)₂VCl₂, (Me₅Cp)₂Ti(Me)₂, (Me₅Cp)₂Zr(Me)₂, (Me₅Cp)₂Hf(Me)₂,(Me₅Cp)₂Ti(OMe)₂, (Me₅Cp)₂Zr(OMe)₂, (Me₅Cp)₂Hf(OMe)₂, (Me₅Cp)₂Ti(OEt)₂,(Me₅Cp)₂Zr(OEt)₂, (Me₅Cp)₂Hf(OEt)₂, (4,7-Me₂Ind)₂TiCl₂,(4,7-Me₂Ind)₂ZrCl₂, (4,7-Me₂Ind)₂HfCl₂, (4,7-Me₂Ind)₂VCl₂,(4,7-Me₂Ind)₂Ti(Me)₂, (4,7-Me₂Ind)₂Zr (Me)₂, (4,7-Me₂Ind)₂Hf(Me)₂,(4,7-Me₂Ind)₂Ti(OMe)₂, (4,7-Me₂Ind)₂Zr(OMe)₂, (4,7-Me₂Ind)₂Hf(OMe)₂,(4,7-Me₂Ind)₂Ti(OEt)₂, (4,7-Me₂Ind)₂Zr(OEt)₂, (4,7-Me₂Ind)₂Hf(OCH₂CH₃)₂,(2-MeInd)₂TiCl₂, (2-MeInd)₂ZrCl₂, (2-MeInd)₂HfCl₂, (2-MeInd)₂VCl₂,(2-MeInd)₂Ti(Me)₂, (2-MeInd)₂Zr(Me)₂, (2-MeInd)₂Hf(Me)₂,(2-MeInd)₂Ti(OMe)₂, (2-MeInd)₂Zr(OMe)₂, (2-MeInd)₂Hf(OMe)₂, (2-MeInd)₂Ti(OEt)₂, (2-MeInd)₂Zr(OEt)₂, (2-MeInd)₂Hf(OEt)₂, (2-arilInd)₂TiCl₂,(2-arilInd)₂ ZrCl₂, (2-arilInd)₂HfCl₂, (2-arilInd)₂VCl₂,(2-arilInd)₂Ti(Me)₂, (2-arilInd)₂Zr (Me)₂, (2-arilInd)₂Hf(Me)₂,(2-arilInd)₂Ti(OMe)₂, (2-arilInd)₂Zr(OMe)₂, (2-arilInd)₂Hf(OMe)₂,(2-arilInd)₂Ti(OEt)₂, (2-arilInd)₂Zr(OEt)₂, (2-arilInd)₂Hf (OEt)₂,(4,5,6,7-H₄Ind)₂TiCl₂, (4,5,6,7-H₄Ind)₂ZrCl₂, (4,5,6,7-H₄Ind)₂HfCl₂,(4,5,6,7-H₄Ind)₂VCl₂, (4,5,6,7-H₄Ind)₂Ti(Me)₂, (4,5,6,7-H₄Ind)₂Zr(Me)₂,(4,5,6,7-H₄Ind)₂Hf(Me)₂, (4,5,6,7-H₄Ind)₂Ti(OMe)₂,(4,5,6,7-H₄Ind)₂Zr(OMe)₂, (4,5,6,7-H₄Ind)₂Hf(OMe)₂,(4,5,6,7-H₄Ind)₂Ti(OEt)₂, (4,5,6,7-H₄Ind)₂Zr(OEt)₂,(4,5,6,7-H₄Ind)₂Hf(OEt)₂, (9-MeFlu)₂TiCl₂, (9-MeFlu)₂ZrCl₂,(9-MeFlu)₂HfCl₂, (9-MeFlu)₂VCl₂, (9-MeFlu)₂Ti(Me)₂, (9-MeFlu)₂Zr(Me)₂,(9-MeFlu)₂Hf(Me)₂, (9-MeFlu)₂Ti(OMe)₂, (9-MeFlu)₂Zr(OMe)₂,(9-MeFlu)₂Hf(OMe)₂, (9-MeFlu)₂Ti (OEt)₂, (9-MeFlu)₂Zr(OEt)₂,(9-MeFlu)₂Hf(OEt)₂.

Non-limiting examples of inert organic solvents that may be used forsolubilizing said metallocene are: toluene, cyclohexane, n-hexane,n-heptane, n-octane and/or mixtures thereof.

One uses an amount sufficient to suspend the material.

The amount of said metallocene that may be used in the present inventionranges from 0.1 to 10% by mass of the metal with respect to the mass ofthe catalytic hybrid support, preferably from 0.1 to 2%. The reactiontemperature should range from 0 to 60° C., preferably from 10 to 30° C.The reaction time should range from 0.1 h to 24 h, preferably from 0.5to 4 hours.

After reacting the metallocene with the impregnated hybrid catalyticsupport, the solid product obtained (supported metallocene catalyst) iswashed, and the solvent contained in the product is removed.

The washing of the supported metallocene catalyst obtained is carriedout with a sufficient amount of organic solvent. The wash temperaturemay range from room temperature to 70° C. Non-limiting examples oforganic solvents include: toluene, cyclohexane, n-hexane, n-heptane andn-octane.

The removal of the supported metallocene catalyst is made with reducedpressure in a time ranging from 1 to 24 h with a vacuum pump.

The contents of metal of the group 2 or 13 of the periodic table in thesupported metallocene catalysts range from 1 to 60%.

The contents of metal of the group 4 or 5 of the periodic table in thesupported metallocene catalysts range from 0.1 to 10%.

The supported metallocene catalysts of the present invention aresuitable for being used in processes of homopolymerizing ethylene andco-polymerizing ethylene with α-olefins in suspension or gas phaseprocesses. The α-olefins are selected from: propene, 1-butene, 1-hexene,4-methyl-1-pentene, 1-octene and 1-docedene.

The supported metallocene catalysts of the present invention exhibitcatalytic activity ranging from 20 to 10000 kg inch/mole M·h.

During the ethylene homopolymerization process and ethyleneco-polymerization process with α-olefins, one uses, in addition to thesupported complex of the present invention, an alkylaluminumco-catalyst, the preferred forms being MAO, TMAL, TEAL or TIBAL.

The molar ratio of co-catalyst/catalyst (Al/M) ion the ethylenehomopolymerization and co-polymerization ranges from 500 to 2000,preferably from 1000 to 1500.

The homopolymers and copolymers obtained with the supported metallocenecatalysts of the present invention exhibit a broad distribution of molarmass, comprising Mw/Mn in the range from 2 to 200 and Mw in the rangefrom 100 to 200 kg/mole.

For a better understanding of the invention and of the improvementsachieved, one presents hereinafter a few comparative examples andembodiment examples, which should not be considered limitative of thescope and reach of the invention.

In the examples of the present invention, which should not be consideredlimitative, TEOS (Merck, >98% purity) and octadecyltrimethoxysilane(Aldrich, 90% purity), ethanol (Merck, 99.8% purity) and ammoniasolution (Dinâmica, 25% ammonia), TEAL (Akzo, 10% Al), MAO (Akzo, 10%Al) and the biscyclopentadienyl zirconium IV chloride (Boulder) are usedwithout previous purification.

Toluene (Nuclear, 98% purity) and 1-hexene (Merck), used in preparingthe supported metallocene catalyst and in co-polymerizing ethylene withalpha-olefins, is dried according to the conventional techniques. Allthe manipulations were carried out by using inert nitrogen atmospherewith maximum limit of 1.5 ppm of humidity.

Example 1 describes the preparation of a non-hybrid silica support(comparative). Examples 2 to 6 describe the preparation of the hybridcatalytic supports with different contents of aliphatic organic groupswith 18 carbon atoms. Examples 7 to 12 illustrate the synthesis ofsupported metallocene catalysts prepared with the supports of examples 2to 6.

EXAMPLE 1: Preparation of a (Comparative) Conventional Catalytic Support

This example illustrates the use of TEOS as an agent for preparing anon-hybrid catalytic support based on silica.

In a solution containing 200 mL ethanol and 40 mL ammonia solution,under stirring of 150 rpm, one adds 10 mL of a solution containing 2 mLTEOS in ethanol. The suspension is left under stirring at thetemperature of 25° C. for 2 h, and the resulting solid is dried, washedwith ethanol and dried again in vacuum.

This component obtained was characterized, exhibiting the followingcharacteristics:

C content:

2.5% (w/w)—FIG. 1.

The use of TEOS without octadecyltrimethoxysilane in preparing thesupport results in a silica with 2.5% carbon. In this case, since thesupport does not have aliphatic organic groups, the organic content isattributed to the presence of residual ethoxyde groups. According toFIG. 1, this support exhibits a spherical morphology.

EXAMPLE 2: Preparation of Hybrid Catalytic Support

This example illustrates the use of TEOS and octadecyltrimethoxysilaneat the molar ratio of 50:1, as reactants for preparing the hybridcatalytic support having aliphatic organic groups.

In a solution containing 200 mL ethanol and 400 mL ammonia solution,under stirring of 150 rpm, one adds 10 mL of a solution containing 2 mLTEOS in ethanol. The suspension is kept under stirring at thetemperature of 25° C. for 2 h. After this period, one adds, drop bydrop, 5 mL of a solution containing 0.085 mL ofoctadecyltrimethoxysilane in ethanol. The suspension is kept understirring at the temperature of 25° C. for a further 2 hours, and theresulting solid is dried in vacuum, washed with ethanol and dried againin vacuum.

This component obtained was characterized, exhibiting the followingcharacteristics:

C content: 5.1% w/w).

The carbon content obtained for this support (5.1%) is higher than thatobserved in the support of the comparative example (Example 1), whichdemonstrates the incorporation of the hydrocarbon groups of theoctadecyl type (with 18 carbon atoms) in the support and, therefore,proves the formation of the hybrid support.

EXAMPLE 3: Preparation of the Hybrid Catalytic Support

This example illustrates the use of TEOS and octadecyltrimethoxysilaneat the molar ratio of: 20:1, as reactants for preparing the hybridcatalytic support provided with aliphatic organic groups.

In a solution containing 200 mL ethanol and 400 mL of ammonia solution,under stirring of 150 rpm, one adds 10 mL of a solution containing 2 mLof TEOS in ethanol. The suspension is kept under stirring at thetemperature of 25° C. for 2 h. After this period, one adds, drop bydrop, 5 mL of a solution containing 0.21 mL of octadecyltrimethoxysilanein ethanol. The suspension is kept under stirring at the temperature of25° C. for a further 2 h, and the resulting solid is dried in vacuum,washed with ethanol and dried again in vacuum.

This component obtained was characterized, exhibiting the followingcharacteristics:

C content: 10.8% (w/w)—FIG. 2.

The carbon content obtained for this support (10.8%) is higher than thatobserved in the support of Example 2, which demonstrates a larger numberof hydrocarbon groups of the octadecyl type (with 18 carbon atoms) inthis support. According to FIG. 2, this support exhibits a sphericalmorphology with lamellar covering.

EXAMPLE 4: Preparation of the Hybrid Catalytic Support

In a solution containing 200 mL ethanol and 400 mL of ammonia solution,under stirring of 150 rpm, one adds 10 mL of a solution containing 2 mLof TEOS in ethanol. The suspension is kept under stirring at thetemperature of 25° C. for 2 h. After this period, one adds, drop bydrop, 5 mL of a solution containing 0.42 mL of octadecyltrimethoxysilanein ethanol. The suspension is kept under stirring at the temperature of25° C. for a further 2 h, and the resulting solid is dried in vacuum,washed with ethanol and dried again in vacuum.

This component obtained was characterized, exhibiting the followingcharacteristics:

C content: 19.8% (w/w)—FIG. 3.

The carbon content obtained for this support (19.8%) is higher than thatobserved in the support of Example 3, which demonstrates a larger numberof hydrocarbon groups of the octadecyl type (with 18 carbon atoms) inthe support. According to FIG. 3, this support exhibits a sphericalmorphology with lamellar domains.

EXAMPLE 5: Preparation of the Hybrid Catalytic Support

This example illustrates the use of TEOS and octadecyltrimethoxysilaneat the molar ratio of 5:1, as agents for preparing the hybrid catalyticsupport provided with aliphatic organic groups.

In a solution containing 200 mL ethanol and 400 mL of ammonia solution,under stirring of 150 rpm, one adds 10 mL of a solution containing 2 mLof TEOS in ethanol. The suspension is kept under stirring at thetemperature of 25° C. for 2 h. After this period, one adds, drop bydrop, 5 mL of a solution containing 0.84 mL of octadecyltrimethoxysilanein ethanol. The suspension is kept under stirring at the temperature of25° C. for a further 2 h, and the resulting solid is dried in vacuum,washed with ethanol and dried again in vacuum.

This component obtained was characterized, exhibiting the followingcharacteristics:

C content: 37.3% (w/w)—FIG. 4.

The carbon content obtained for this support (37.3%) is higher than thatobserved in the support of Example 4, which demonstrates a larger numberof hydrocarbon groups of the octadecyl type (with 18 carbon atoms) inthis support. According to FIG. 4, this support exhibits a spherical andlamellar morphology.

EXAMPLE 6: Preparation of the Hybrid Catalytic Support

This example illustrates the use of octadecyltrimethoxysilane withoutTEOS as a reactant for preparing the hybrid catalytic support providedwith aliphatic organic groups.

In a solution containing 200 mL ethanol and 40 mL of ammonia solution,under stirring of 150 rpm, one adds 10 mL of a solution containing 2 mLof octadecyltrimethoxysilane in ethanol. The suspension is kept understirring at the temperature of 25° C. for 2 hours, and the resultingsolid is dried, washed with ethanol and dried again in vacuum.

This component obtained was characterized, exhibiting the followingcharacteristics:

C content: 68.6% (w/w)—FIG. 5.

The carbon content obtained for this support (68.6%) is higher than thatobserved in the support of Example 5, which demonstrates a larger numberof hydrocarbon groups of the octadecyl type (with 18 carbon atoms) insupport. According to FIG. 5, this support exhibits a lamellarmorphology.

Considering the results of Examples 2 to 6, the increase in the numberof hydrocarbon groups of the octadecyl type in the support entails anincrease in the domains with lamellar morphology and, consequently,reduction of the sphericity of the support particles.

EXAMPLES 7-12: Preparation of the Supported Metallocene Catalyst

In 50 mL of toluene, under stirring of 150 rpm, one suspends 1 g of thehybrid catalytic support obtained according to the examples describedabove. To the suspension one adds 2 mL of TEAL solution at a temperatureof 25° C. This suspension is kept at this temperature and under stirringfor 1 hour. After this period, in the same experimental conditions, oneadds to the suspension 10 mL of a solution containing 32 mg ofbiscyclopentadienyl zirconium IV chloride in toluene. The reaction iscarried out in a 2-hour period. After this period, the resulting solidis dried, washed with toluene and dried again in vacuum.

The results of contents of Al and Zr for the supported metallocenecatalysts obtained with the hybrid catalytic support of Examples 1-6 arepresented in Table 1.

TABLE 1 Results of the contents of Al and Zr for the supportedmetallocene catalysts obtained from the hybrid catalytic supports asdescribed in Examples 1 to 6. Supported Content Content Metallocene ofAl of Zr Hybrid catalytic support catalyst (% w/w) (% w/w) Example 1Example 7 1.0 0.5 Example 2 Example 8 8.6 0.5 Example 3 Example 9 7.20.5 Example 4 Example 10 n.d. 0.2 Example 5 Example 11 1.1 0.1 Example 6Example 12 n.d. 0.3 n.d.: Not determined.

According to Table 1, the Al content in the supported metallocenecatalysts prepared with the supports of Examples 1 to 6 ranges from 1 to9%. These results demonstrate the presence of TEAL in the composition ofthe supported metallocene catalysts. The Zr contents in the supportedmetallocene catalysts range from 0.1 to 0.5%. One observes that, for thecatalysts synthesized with the supports prepared by using TEOS (Examples7-11), the systems with higher contents of octadecyl groups exhibitcontent of Zr and, therefore, of immobilized metallocene complex(Examples 10 and 11). For systems with lower contents of octadecylgroups (Examples 8 and 9), there is no reduction of the contents of theimmobilized metallocene complex as compared with the metallocenecatalytic system prepared by using the non-hybrid support (Example 7).

EXAMPLE 13: Polymerizations

In a glass reactor with 300 mL capacity and under magnetic stirring, oneadds toluene in nitrogen atmosphere. The temperature is adjusted to 60°C. with the aid of a thermostatized bath. An amount of 10 mL of TEAL isadded for washing the reactor. The washing time is of at least thirtyminutes. The wash liquid is removed from the reactor by siphoning. Afterwashing the reactor, one adds toluene and MAO and then the reactor ispurged with ethylene. Once the purging has been carried out, themetallocene catalyst supported in a hybrid support, dissolved intoluene, is added to the reactor, forming a catalytic system withconcentration of Zr of 10⁻⁶ Mole/L and with Al/Zr ratio preferably of1500. The ethylene pressure is adjusted to 1.6 atm, and polymerizationis carried out for 30 min. the resulting polymer is precipitated inacidified ethanol solution, filtered, washed with water and ethanol anddried in an oven in vacuum. For copolymerization, 15 mL of 1-hezen areadded just before adding the supported metallocene catalyst.

The results of catalytic activity in the polymerization of the ethyleneof the supported metallocene catalysts obtained with the hybridcatalytic supports of spherical and/or lamellar morphology are presentedin Table 2.

TABLE 2 Catalytic activity obtained in the polymerization of theethylene by using supported metallocene catalysts. Catalytic activitySupported metallocene catalyst (kg pol/mole Zr · h) Example 7 30 Example8 690 Example 8* 870 Example 9 860 Example 10 310 Example 11 450 Example12 200 *In this case, a co-polymerization of ethylene with 1-hexene wascarried out.

According to Table 2, the supported metallocene catalysts prepared withthe hybrid supports provided with octadecyl groups (Example 8-12)exhibit catalytic activities superior to that observed for the supportedmetallocene catalyst prepared by using a non-hybrid support of Example 7(comparative).

The results of the properties of the polymers formed are presented inTable 3 below.

TABLE 3 Properties of the polymers obtained with supported metallocenecatalyst. Supported metallocene catalyst Tm (° C.) Mw (kg/mole) Mw/MnExample 7 132 240 2.2 Example 8 133 450 3.6 Example 8* 112 170 5.4Example 9 133 250 6.1 Example 10 133 360 2.6 Example 11 133 580 3.5Example 12 133 680 2.9 *In this case, a co-polymerization of ethylenewith 1-hexen was carried out.

According to Table 3, the ethylene polymers produced by using thesupported metallocene catalysts prepared with the hybrid supports havingoctadecyl groups (Examples 8-12) exhibit molar masses (Mw) higher thanthat observed for the ethylene polymer produced with the metallocenecatalyst of Example 7 (comparative). With regard to the distribution ofmolar mass (Mw/Mn) of the polyethylenes, the polymers produced by usingthe supported metallocene catalysts prepared with the hybrid catalyticsupports having octadecyl groups (Examples 8-12) have broadened valueswith respect to that observed for the polymer produced with themetallocene catalyst of Example 7 (comparative), which suggests betterprocessability of the polymers prepared with the catalysts of thepresent invention. In addition to the broadening of the polydispersion,the polymers obtained with the supported metallocene catalysts of thepresent invention exhibit a bimodal molar mass distribution, as can beobserved in FIGS. 6 and 7, unlike the polymer prepared with the catalystof the comparative example (Example 7), wherein the molar massdistribution is unimodal (FIG. 8).

These results demonstrate that the broadening of the molar massdistribution of the polyethylenes is achieved by using a single type ofimmobilized metallocene complex in the supports and is the effect of themodification of inorganic component by the aliphatic organic groups.

Therefore, the considerations and examples of the present specificationdemonstrate the distinctive points of the present invention with respectto the prior art, which make the inventive process non-suggested andnon-evident in the face of the literature published on the subject.

A preferred example of embodiment having been described, it should beunderstood that the scope of the present invention embraces otherpossible variations, being limited only by the contents of theaccompanying claims which include the possible equivalents.

What is claimed is:
 1. A metallocene catalyst supported in a hybridsupport, comprising: (I) at least one metallocene derived from acompound of formula 1:[L]₂-MQ₂  formula (1) wherein: M is a transition metal of group 4 or 5of the periodic table; Q comprises: halogen radical, aryl radical, alkylradical containing 1 to 5 carbon atoms or alkoxy radical containing from1 to 5 carbon atoms; and L is a ligand selected from: cyclopentadienyl,indenyl or fluorenyl, optionally substituted with hydrogen, alkyl,cycloalkyl, aryl, alkenyl, alkylaryl, arylalkyl or arylalkenyl, attachedto the transition metal by bonding; (II) a hybrid catalytic supporthaving at least one inorganic silica component and aliphatic organicgroups chemically bonded to the inorganic silica component, wherein thealiphatic organic groups are on both the surface and inside theinorganic silica component; and (III) at least one organometalliccompound containing a metal selected from group 2 or 13 of the periodictable, and wherein the aliphatic organic groups comprise a chaincontaining from 8 to 22 carbon atoms and are homogeneously dispersedthroughout the inorganic silica component.
 2. The supported metallocenecatalyst as recited in claim 1, wherein the contents of aliphaticorganic groups measured through carbon content range from 0.5 to 80% bymass.
 3. The supported metallocene catalyst as recited in claim 1,wherein the hybrid catalytic support is obtained by means of hydrolyticsol-gel.
 4. The supported metallocene catalyst as recited in claim 1,wherein the metal contents of the group 4 or 5 range from 0.1 to 10% bymass of metal with respect to the mass of the catalytic hybrid support.5. The supported metallocene catalyst as recited in claim 1, wherein themetal contents of the group 2 or 13 of the periodic table ranges from 1%to 60% by mass with respect to the total mass of the supported catalyst.6. The supported metallocene catalyst as recited in claim 1, wherein theorganometallic compound is selected from: trimethylaluminum (TMAL),triethylaluminum (TEAL), triisobutylaluminum (TIBAL),tri-n-hexylaluminum (TNHAL), tri-n-octylaluminum (TNOAL),dimethylaluminum (DOMAC), methylaluminum dichloride (MADC),diethylaluminum chloride (DEAC), ethylaluminum dichloride (EADC),di-isobutylaluminum chloride (DIBAC), isobutylaluminum dichloride(MONIBAC), ethylmagnesium butyl (BEM), butyl octylmagnesium (BOMAG),methylmagnesium chloride, ethylmagnesium chloride or mixtures thereof.